HISTOCHEMICAL INVESTIGATIONS ON THE DISTRIBUTION OF ADRENERGIC AND CHOLINERGIC NERVES IN THE MALE GENITAL ORGANS

Abstract

Many details concerning the innervation of the genital organs remain as yet unknown, especially of the testis, epididymis, ductus deferens, prostate and penis, which participate in spermatogenesis, ejaculation and erection. Scarcely any histochemical studies have been carried out on the peripheral distribution of their nervous supply.
The localization of adrenergic and cholinergic nerves in the genital organs was clarified by light microscopy and comparative studies on the innervation of these structures between dog and man were conducted. The following results were obtained.
The study of distribution of catecholamine (CA) fluorescent nerve fibers and acetylcholinesterase (AChE) positive nerve fibers within normal genital organs revealed a relatively abundant distribution of CA fluorescent fibers and AChE positive fibers in the testis in both dog and man. These fibers were noted both in the interstitial tissue and in the vascular wall of the interstitial tissue.
In the epididymis, CA fluorescent fibers and AChE positive fibers were noted rather abundantly in the muscular layer and interstitial tisue. No difference was noted according to their locations such as the head, body and tail.
In the ductus deferens, these nerve fibers were abundant in the muscular layer and submucosal tissue, without any differences related to their location.
In the prostate, AChE positive fibers were noted as abundant in the muscular layer, interstitial tissue and around the blood vessels, while CA fluorescent fibers were relatively scarce, being seen to a slight degree only in the muscular layer and interstitial tissue.
No difference was noted between man and dog, as to the distribution of both of these nerves in the testes epididymis, ductus deferens and prostate.
On the other hand, the CA fluorescent fibers in the corpus cavernosum of the human penis are relatively infrequent. They were seen along the vascular wall and smooth muscle fibers within the trabeculae. In the dog, the fluorescence of the elastic fibers was marked, which made their differentiation from CA fluorescent fibers difficult. Abundant AChE positive fibers were found between the trabeculae of the cavernous body of the human penis. None of these were noted in the dogs whatsoever. In the penis of man and dog, the distribution of these nerve fibers was completely different from that observed in the above described studies. Thus, in some organs, it is dangerous to apply the results obtained in experiments with dogs directly to man.
As the result of studies on the effects of the simultaneous section of the hypogastric nerve, pelvic nerve and pudendal nerve on CA fluorescent nerve fibers and AChE positive nerve fibers in the genital organs, no marked difference was noted between the experimental and control normal dogs.